Ink-jet recording method and ink composition set

Abstract

An ink composition set including an ink composition. A containing at least a colorant and an interior curable photopolymerization initiator, and an ink composition B containing at least a polymerizable compound, a surface curable photopolymerization initiator and a polymerization accelerator, and an ink-jet recording method using the ink composition set.

1. An ink set comprising:
 (1) a white ink composition A comprising at least a colorant and one or more photopolymerization initiators, including at least a first photopolymerization initiator, said first photopolymerization initiator comprising at least 60% by weight of a total amount of the one or more photopolymerization initiators of the white ink composition A; and 
 (2) a transparent ink composition B comprising at least a polymerizable compound, a polymerization accelerator and one or more photopolymerization initiators, including at least a second photopolymerization initiator, said second photopolymerization initiator comprising at least 60% by weight of the one or more photopolymerization initiators of the transparent ink composition B; 
 
       wherein the first photopolymerization initiator is more effective than the second photopolymerization initiator in promoting curing of an interior of a photocurable coating formed by ejecting white ink composition A onto a recording medium and then ejecting transparent ink composition B onto white ink composition A, said first photopolymerization initiator decomposing upon absorption of ultraviolet light to form residues that do not absorb ultraviolet light, and 
       wherein the second photopolymerization initiator is more effective than the first photopolymerization initiator in curing a surface of the photocurable coating, said second photopolymerization initiator being capable of suppressing polymerization inhibition due to permeation of oxygen. 
     
     
       2. An ink-jet recording method for forming a coating on a recording medium, the method comprising the steps of:
 (a) providing the ink set of  claim 1 ; 
 (b) attaching the ink composition A and the ink composition B to a recording medium by (i) ejecting the ink composition A to form a first, colorant layer on the recording medium; and then (ii) ejecting the ink composition B to form a second, transparent layer on the colorant layer formed in step (b)(i); and 
 (c) irradiating the ejected compositions with an ultraviolet ray to form an image through ultraviolet ray curing. 
 
     
     
       3. The ink-jet recording method as claimed in  claim 2 , wherein the second photopolymerization initiator is an α-aminoketone. 
     
     
       4. The ink-jet recording method as claimed in  claim 3 , wherein the first photopolymerization initiator is an acylphosphine oxide. 
     
     
       5. The ink set as claimed in  claim 1 , wherein the second photopolymerization initiator is an α-aminoketone. 
     
     
       6. The ink set as claimed in  claim 5 , wherein the first photopolymerization initiator is an acylphosphine oxide.